Water craft and propulsion means therefor



Dec. 15, 1 J, HQRAN WATER CRAFT AND PROPULSION MEANS THEREFOR 7 Sheets-SheeiI l Filed Deo.

Dec. 15, 1964 Filed Dec. 3l, 1962 F ig. 25:5

J. J. HORAN WATER CRAFT AND PROPULSION MEANS THEREFOR Fig,

7 Sheets-Sheet 2 Dec. 15, 1964 .1.J. HoRAN 3,161,173

WATER CRAFT AND PRoPULsIoN MEANS THEREFOR Filed Deo. 5l, 1962 7 Sheets-Sheet 3 Dec. l5, 1964 .1.J. HoRAN WATER CRAFT AND PRoPULsIoN MEANS THEREFOR 7 Sheets-Sheet 4 Filed Dec.

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Dec. 15, 19.64 J. J. HORAN WATER CRAFT AND PRoPuLsIoN MEANS THEREFOR 7 Sheets-Sheet 5 Filed Deo.

Dec. 15, 1964 J. J. HoRAN 3,161,173

WATER CRAFT AND PROPULSION MEANS THEREFOR Filed Dec. 5l, 1962 '7 Sheets-Sheet 6 Dec. 15, 1964 J. J. HoRAN 3,161,173

WATER CRAFT AND PRoPULsIoN MEANS THEREFOR Filed Deo. 31, 1962 7 Sheets-Sheet 7 @5f/XW 7 fl |28 United States Patent p 3,161,173 WATER CRAFT AND PRPUIJSIN MEANS THEREFGR .lohn Si. Horan, 420 Quigley Ave., Willow Grove, Pa. Filed Dec. 31, 1962., Ser. No. 248,4226 13 Claims. (Cl. 11S- 76) This invention relates to self-powered Water-planing devices.

Several devices have the general objective of providing water skiers with nontowing propulsion means. These devices have been generally characterized by one or more of the following disadvantageous attributes: bulky, cumbersome, heavy, top-heavy, ditlicult to maneuver, costly, etc. Often impracticable or scarcely functionable, they tend to turn turtle and drown their engines when the operator loses control or falls olf.

For maximum value as a sport, the skier should exercise the maximum of control with the least effort; but the control should be immediate and direct; servo systems and power supplies would be out of place. The best way to achieve unity between the skier and his planing device is, first, to free him from the tow-line and, second, to reduce the number of components and the total weight and bulk of the apparatus to the absolute minimum.

The Sea-Skimmer Water craft of this invention are inherently balanced by the strategic arrangement of the right kind and irreducible number of components in the most inherently stable array. The component designs are unique, the combination has no parallel, and the fact that the tidy concept is complete in a small number of small components yielding hot and agile performance emphasizes the points of distinction from the existing art.

Others have provided Outrigger iloats, large water-tight hulls that are true boats, broad based platforms, and other elaborate structures for conventional engine mounting and for prevention of capsizing, the sport being obscured in the shadow of the apparatus.

Top-heavy outboard engines cause skiing platforms to overturn when the skier engages in a tight maneuver or falls off. This not only terminates the excursion but requires immediate and expensive disassembly, purging of salt water, and possibly complete overhaul. Outriggers and broad platforms mitigate the instability only partly, at the cost of rendering the apparatus stiif, clumsy and slow to respond.

Inboard arrangements of land-type engines, of lawnmower and motorcycle types, are equally unsuited for the skiing environment.

The distinctive engines of this invention actually thrive and function best in an environment hostile to other types of small internal-combustion engines. Instead of measures to remove them from Contact with water, even salt water, the engines of the Sea-Skimmer actually run with wet skins. They are located where, but for ordinary vulnerability, an engine for a skiing device ought to go, that is, below, where the small weight can not only be tolerated but actually employed to advantage.

In the Sea-Skimmer, the engine, instead of being a creator of an overturning moment, actually furnishes a ballasting or stabilizing moment, thus affording inherent stability. Since the Sea-Skimmer resists overturning (other than deliberate, it being very small and light) it will withstand long periods of usage without contributing mishap to a skiers enjoyment.

An object of this invention is to provide an engineequipped device for skiing, the device being of minimum size, weight, cost, complexity and upkeep, and at the same time affording maximum ease of balance, controllability, acceleration, speed, maneuverability, stability, safety, and other desirable aspects.

An object of this invention is to provide for use in 19a/whim Patented Dec.. l5, 1964 said device and in other water craft of high performance and small size, an internal-combustion engine capable of withstanding operation as a prime mover while immersed in water without drowning An object of this invention is to make it possible to achieve very high performance in extremely small water craft adapted to carry an operator or skier.

An object of this invention is to provide engines that include simple means for protecting them against waterimmersion environments and of achieving power-weight* and performance-weight ratios and attributes not otherwise achievable.

An object of this invention is to enhance the dynamic characteristics achievable with light-weight engines.

While a watercraft employing some of the inventive principles disclosed herein would be far superior to related devices even without these engines, the highest performance requires that the engine teachings also be adopted. Further objects and inventive features will become apparent in the balance of the specication, the claims and the drawings, in which:

FIG. l is a drawing, largely sectioned, of an engine for the Sea-Skimmer;

FIG. 2 is a sectioned sketch showing the compensatory unbalancing of a crank member for the engine of FIG. 1;

FIG. 3 is a partially sectioned view at a right angle to FIG. l;

FIG. 4 is a view from beyond the cylinder head of the engine of FIGS. 1 to 3;

FIG. 5 is a fragmentary section showing surfaces cut by plane S-5 of FIG. 1;

FIG. 6 is a cross section through the gas ports of the engine of FIGS. 1 to 5;

FIG. 7 views the spark gap zone of the engine of FIGS. l to 6;

FIG. 7A is a sectioned drawing of the spark-gap zone at a right angle to FIG. 7;

FIG. 8 is a cutaway view of the FIG. l engine installed in a Sea-Skimmer;

FIG. 9 is a top view of the Sea-Skimmer of FIG. 8;

FIG. 9A is a fragmentary View of a portion of a skiboard, like that in FIG. 9, but with an alternate form of side thrust rail;

FIG. 10 is a cutaway view of a second engine installed in a second Sea-Skimmer;

FIG. 11 is a view of the engine only of FIG. l from above;

FIG. 12 is a view from above of the Sea-Skimmer of FIG. 10;

FIG. 12A is a section through the skiboards of the Sea-Skimmer of FIG. 12;

FIG. 13 shows a form of flotation alternative to that shown in FIG. 10;

FIG. 14 shows a training modification of the Sea- Skimmer;

FIG. 15 shows a second training modification of the Sea-Skimmer;

FIG. 16 is a fragmentary View in partial section of a third form of engine;

FIG. 17 is a fragmentary view showing a modification of engine cylinder structure;

FIG. 18 is a View of one manner of installing the engine of FIG. 10 in a tiny passenger-carrying racing boat;

FIG. 19 is a view of another manner of installing the engine of FIG. 1) in a tiny racing craft.

Referring now generally to FIGS. l through 9 and particularly to FIGS. 1 through 7A, there is shown a unique form of small engine. To those familiar with the relatively bulky contours of lawnmower and outboard engines, the engine will appear starkly slim, simple, and

l in section in FIGS. 1 and 6.

uncluttered, and its power, based onr overall cubage relative to known engines, may be underestimated. It is unusually long in proportion'to its other dimensions, ay

characteristic that enhances its ability to yield maximumspeed performance while itself immersed in water.

While a 2-stroke cycle engine has been chosen for exemplitcation of principles, many of theinventive concepts are also applicable to 4-stroke engines.

The engine head 21., which includes a simple domedV 'cant, is held in place under the wrench ilats 31 of the spark plug 23. v

The unique cylinder and porting arrangement reduces the number of components forming the outer wall ofthe engine, thereby eliminating joints, seams, and plugs, drilled and tiled openings, and the necessity for sealing such items. Besides the head 21, the outer surfaces of the engine consist only of three other multi-function castings, rthe lower wall 32, theupper wall 33, and theV end Wall 34. The cylinderl sleeve 36 is tted between the lower wall 32 and the upper wall 33,`held in place by its flange under head 21 and sealed with gasket 58. The

casting arrangement and the pantly self-supported sleeve 36 are adapted for high-production offmaXimum-effectiveness gas ports, without time-consuming hand-routing and filing, because these ports are fully defined as an Vearly step in automated fabrication of the 'sleeve and because the gas passageways Acan be adequately delined in castingsleeve clearances. The intake port groups 37, *37 are each a closely grouped set of punched oblong holes, seen Since the lexhaust ports 38 cannot appear in the yhalf of the engine exposed by the sectioning of FIG. l, dotted rectangles 38 show the relative position these ports oc cupied in the cut-away portion-of FIG. l. The physical arrangement not only provides a breathing capability adequate for racing type engines, it also makes it unnecessary to hand-work the portsfand, further, eliminates thel need for applying sealing plugs, y port covers, etc.in or on the cast walls 32, 33 to seal the usual paths of access for hand work. Such plugs, etc., would, ofcourse, be especially undesirable in the environment for which the engine was invented. f

The cast walls clear the'self-snpporting cylinder sleeve 36 below the intake ports 37, to provide well configured passageways 39, 39 which, porting through the cylinder walls, impart a desired upward velocity component to the gases issuing into the cylinder sleeve 36.- The ow through the two longitudinal passageways 39, 39 tendsY to be equalized by the two large intercommunicating cross-passageways 40 between the wall castings 32, 33 and the outside walls at the skirt portion ofthe sleeve 36, which is completely self-supporting at thislower end.

These vgases also receive an inward velocity component;

as they issue into the cylinder36, as best inferred*v from FIG'. 6. The twofinward-boun'd but upward-inclined gas .the fact of loop portingbut rather the means ofobtaining The exhaust stack 43 is aimed vertically upward as the gases leave the cylinder. The stack 43, as seen in FIG. 8, terminates in cross-header 44,V the lip 45 of which stack 43 extends upwardly inside the header 44v as a fence against the possibility of water washback through header; 44. The lower endv of header 44, which will usually be below water, is equipped with a light-weight, disc-typel check valve 118, closable by both gravity and waterwashback. VThe .lightness of check valve 118 imposes the minimum of throttling of the escaping gases. The stack 43 and header 44, together, comprise a gas trap.

The two-ringed piston 19, its conventionalwristpin and connecting rod 46, the latter being preferably equipped with needle bearings 119 at both ends, constitute Vthe reciprocating components of this engine, which has no crankshaft. Piston force is transmitted by crankpin 47 Vto two rotating crank members,fusually termed crankwheels in this specification because of the shape chosen 48, 49, though they need not be circular, as will be seen.

` Crankwheels 48, 49 ride, preferably aided by ball bearings 50,V 50, on journaledV surfaces hereinV designated as pintles 51, 52, respectively, pintles 51, 52 being-preferably cast integrally with the .respective lower and upper walls 32, 33. Crankpin 47 may be Yintegral with one or both of the Vcrankwhe'els or it may be braZe-bonded' (64y in FIG. 2) or otherwise secured to one or both crankwheels.

One or both crankwheelsV 48, 49 may be unbalanced by selective lightening, as seen in FIG. 2, aiording'far better'smoothingaction than When eccentric Weights or iiywheels are located and/ or reacted anywhere other than immediately close to connecting rod 46. To compensate for the reciprocating masses of piston, wrist pin, connec'z'tr ing rod, and crankpin, the mass of the crankwheels is unbalanced so that the heavier region will be diametrically opposite crankpin 47. In FIG. 2, which shows one of several possible forms of construction, Crankwheel 48 is shown in section, with slices 66, 66 milled-y out therefrom, following which operation, the crank pin 47 and the cover ring 121 have been inductively brazedinto position, preferablyA with copper or silver foil-interlayers 64,V 64. The purpose of the cover ring 121 is tofst i thev crankcase so. as to produce highercrankcase pressures on the downstroke of the piston, as mayy be desirable for increasing injection pressure and, thus,'h'iglt-speed'torque.

VIf more high-speed rtorque is not desired, ring 121 may be omitted and the Crankwheel willbev milled full-thick.-

ness at 66 and will no longer Ybe wheel-shaped.

One crankwheel, conveniently 49, has two peripherally spaced magnets 75, 75,one of which is seen, as" a dotted outline, in FIG. 1.- The magnets are in peripherally matched relationship to function cooperatively with:

Ymagneto assembly 128, best seen in section in FIG. 3.

Magneto assembly 12S has been screwed to upper `walll 33, with gasket 352 interposed under its flange; Magneto assembly 128 is a potted assembly containing a stack 53 of E laminations, a coil 54- surrounding the middle Ylegof Vthe E, and a condenser also potted thereinto but Vnot seen fin the drawing. The E lamination stack-hasl nts legs projecting through wall 33 to approach `closely, within a few thousandths of an inch, Ito the surface' of the spinningI magnets on crankwheel 49. The approach can Vbe closer than that ofthe conventional magneto stack streams collide along the left portion o f the diameter,Y

because of the asymmetrical arrangement of passageways 39 and intake ports 37. The flow resultant being up-` ward, the scavenging action washes the spark-plug zone before Vexcess fuel can be ,lost via the exhaust ports on the to theconventional flywheel which, having a beaming to one side,':su1fers oscillating deflection ofY itsf shaft underv @high-speed operation Vand thus-may rub a closely Vset magnet, fdestroying the magnet and AVperhaps the flywheel.v

right of FIG. 6.V The loop porting achievedl by the simple-construction shown applies Vthe optimum principles of high-performance, racing-cylinder design to theflow of gases, without: the very`expensive hand-tailoring ofthe castings normally required. Whatis new'here is not higher-voltage spark. l'

Tasmania@ assembly rzswhich is Locally grounded; requires only two leads. Y YOne yis Vthe-w'aterproofe'd, eX-I posed, high-tension lead 41, already described.: 4I'llhe other? is the insulated S5 condenser lead 56 from the magneto assembly, which, as shown fragmentarily in FIGS. 3 and 7, feeds through a small hole 57, transversely drilled in the wall of upper casting 33, and is soldered to the insulated stationary point contact 122 of the spark gap system. The stationary point contact 122 is adjustable, as seen in FIG. 7, by loosening binding-head screw 134) and sliding the stationary point contact 122 in an arc against the restraining adjacent arcuate guide surface 34S molded into the top surface of the plastic retainer 124. The movable point contact 123 is assembled to double-leaf spring 59, which fits into plastic retainer 124. Spring 59 is actuated by the rotation against its cam bearing surface 126 of the eccentric upper end of cam pin 61, which tits in proper registry in a matching non-circular hole in crankwheel t9 and extends upwardly into pintle 52, past packings 62, 62, as seen in FIGS. 7 and 7A. The terminus of cam pin 61 is a small-diameter offset portion 125, which, once each revolution of crankwheel 49, forces spring 59 and, with it, contact 123 away from the normally closed position with respect to stationary point contact 122. Thus, the connection between contacts 122 and 123 is opened, causing a high potential to develop in the secondary of magneto c-oil 54 and rire the spark plug 23. Bindingahead screws 132, 132, when loosened, aiford limited freedom for rotating plastic retainer 124, so as to bring graduations 133 into desired registry with spark timing indicator 134, thus adjusting the spark timing. The spark-gap zone is closed by gasketed plate '74.

Backup spring 131 reenforces spring 59 against the tendency to oat at high speed and against resonance.

A second contact point assembly may be fitted into the lower pintle 51. Normally, only one of the two sets of contact points would be permitted to control the tiring at any one time. The second set might serve either of two purposes. Gne would be to use it as a spare. Usually, however, one assembly would have an earlier setting, determined by the angular relationship between the end of the cam pin 61 fitted into crankwheel 43 or by manually setting an adjustment device, such as the retainer previously described. The purpose of the earlier setting would be to aiford choice of earlier ignition when operating at very high rpm. Switching means, not shown, is necessary whenever more than one such spark-gap system is used. Each spark-gap cavity, like the spark-plug chamber, can be fitted with a tiny replaceable desiccant cartridge, such as the one shown at 127.

The crankwheel containing the magnet 75 will normally be made of non-magnetic material chiefly, such as aluminum alloy, high-tensile bronze, or non-magnetic stainless steel. Generally the selection of material will depend on evaluation of the comparative desirability of greatest freedom from vibration achieved by the better balancing that can be obtained with heavy-alloy crankwheels, versus faster acceleration with light-Weight crank members.

The lower crankwheel 48 reacts most of the thrust of the connecting rod, which it transmits to bevel gear portion 63, which may be integral with the crankwheel or separately assembled. Separate assembly is shown in FG. l because of the wider choice of gear cutting machines that can produce the toothed portion when separate.

Bevel gear portion 63 drives bevel gear 67. Any reasonable ratio is feasible between these gears; so it might, therefore, appear preferable to decrease the diameter of gear 67. ln this instance the driven gear 67 was shown to be of equal diameter primarily in order to demonstrate capability of delivering top power from the engine, which has an extremely high r.p.m. capability, without excessively impairing the efficiency of the propeller, as might be the case if the high engine r.p.m. were multiplied to increase further the angular velocity of the propeller.

The only shaftway opening to the water is that provided for the rustless-alloy drive shaft 69, which is sealed by two glands 97, 97, facing both ways so as not to permit compression or fuel loss from the crankcase and, at the same time, to resist any inux of water along the shaftway during the upward stroke of the piston. Bearings are designed to sustain both thrust and radial loads; thus hardened races, as at 98, 98, are indicated wherever bearing balls might otherwise contact non-ferrous materials. End closure 99, containing oppositely faced glands 97, 97 for sealing shaft 69, permits adjustment of pressure and clearance of bearings by means of shims 100 under its flange.

The crankwheels, their arrangements and combinations in this invention afford signiiicant advances in the small-engine art. Obviously, they eliminate the orthodox cross-crankshafting that normally would add to the hazard of leakage in and out and make it necessary to greatly widen the narrow engine. They make it unnecessary to add a conventional flywheel, which would also greatly widen the silhouette, as in conventional engines, and would cause undesirable spray to the annoyance of the skier and the greater hazard of drowning the engine via the air intake. By eliminating the flywheel, they eliminate the crankshaft flexure that normally accompanies its use and the couples that are usually caused by the separation of the flywheel from the cylinder axis. They actually constitute a very close coupled kinetic balancing means, affording maximum reduction of the moments normally incident between the connecting rod and the usually remote dywheel. When the crankwheel mass is deliberately made asymmetrical for balancing reciproeating forces, vibration is controlled by the fact that the crankwheel itself is part of its own bearing.

The close coupling of the crankwheel masses, besides easing the problem of vibration, is a source of both live and dead weight saving. The crankwheels constitute the shortest and the most rigid possible path between connecting rod and bearing; therefore, they make the most vibration-free path; and, when their masses are adjusted to counterbalance reciprocating forces, they are more efiicient than prior devices. Moreover, some of the weight saved may be reinvested to secure an additional percentage of counterbalancing for still greater smoothness.

Fabricated from simple discs, slugs, or extrusions, the crankwheels eliminate the most costly single component in the usual engine, the crankshaft, which is expensive to forge or cast, to machine, to balance, and to inspect, the cost of the usual crankshaft climbing fast as the requirement for precision goes up.

Besides eliminating the crankshaft, its bearings and remote flywheel, the crankwheels permit still further slimming of the engine when the pintles on which they rotate are made to accept the spark-gap system. Still further slimming comes about because the crankwheels Aerein oifer means for including the magnets, instead of relegating the entire electrical system to an outboard position beyondoutlying crankshaft bearings. They indirectly contrlbute still more cooperatively to the slimming and simplification of the engine by virtue of the fiat exterior surface that can be given to the coacting wall 33, which furnishes the pintle 52, thus enormously facilitating and simplifying the carburetor-manifold-reed installations, as shown herein.

The crankwheels may include gear functions, including bevel gear functions for orienting the driveshaft parallel to the piston axis, thus permitting full hydrodynamic advantage to be taken of the extraordinary slirnness of the engine, when the head of the engine is oriented forward, the propeller in line and the fuel system upward, as will be seen. The crankwheels can be fabricated of light or heavy materials for any desired compromise between smoothness and fast acceleration; they can be made magnetic or non-magnetic at choice, with the two crankwheels being of different materials if desired.

The crankwheel inboard of the manifold can even incorporate a centrifugal supercharger if desired.

All advantages listed for crankwheels, except those reiting to the Vfuel system, are equally applicable 'to4 four:Y

troke-cycle engines as well as two-stroke types.

The fuel-air Iintake system is a highlyv distinctive feature f the Sea-Skimmer and its engine. -It is resistant to actors thatnormally drown engines brought accidentally nto-such 4intimate contact with watenthe traditional nemy of internal-combustionengines. Beginning at the rottom of the stack 102 above the reed ports 72, 72, the

ianifold 73, gasketed 7.4 to the flat face of the upper fall 33, receives fuel-air mix from carburetor 101, which s tted at the bottom inside the tall stack 102. .The tack 102 has rubber-plugged access holes 103, 104l to arburetor adjustment screws. Choke and throttle keys .05; 106 slide in via rubber grommets to lit over the quared shaft ends of these two hidden buttery-'valves Above the stack 102, there is fitted a bellows-ltike rubber lose 115 which ends in a breather oat 116. The bottom f the breather float 116 has4 a slab of rigid plastic'foam .07,1 sufficiently buoyant to stretch the hose 116 to its naximum length. The severalV thin upper layers 108, 109, l10above the slab 107 are made of a soft resilient plastic 0am that is capable of curling upwards against a wash Fuel i When centain few components are assembled to the` simple engine just described, the structure becomes theV Sea-Skimmer concept. angine is seen in FIGS. 8 and 9. A single assembly shaft 36 is the key component for assembly. The largetransversehole 274Vin'the wall 34 of the engine accepts shaft fwhich ris also linked to the forward planing board 75 via brackets 7 8, 78 and to left and right ski-boards 7 6, 77 via brackets 79, S0 respectively.-

Where the brackets would otherwise be hidden in FIG.

This structure, including the' 9, they have been outlined by dotted lines.`rv Brackets 79,

90 are identical, kleft andright selection being made by rotating the bracket end Vfor end. Adjusterassembly Y81,

81 fixes the pitch `of the engine-propellerfassembly -versus i the forward planing board." Cowling V82 serves vasf-.an optional means 'of further smoothing-'thev contour of the slim assembly exposed to the ,relatively movingvwater. Plugs 237, which are removable, permit regulating the rate at which the cowling permits water to flow in and out. The. engine will run warmerwhen the plugs are left in place. If it is desired toV operate in salt water, while cooling the engine with lfresh water, the lplugs will all `be secured andthe lill level may be kept slightly higher than Vthe stabilized exchange level. Chain 238111 securesplugv 237 to cowling 82.

Shroud 83 guards the propeller 84 and shaft S5, or,l more properly, guards the skier against contact with these rapidly rotating parts. Terminal cross 86 is an X-shaped guard at the rear of the shroud 83 to prevent entry of any portion of a limb of the skier into the propeller zone. Y'

The forward planing board 75 has a buoyantblock S9, held in .place by long screws 92, 92, washers 93, 93

and winggnuts'94, ,'94, `set in shallow holes in buoyantI block 89. Theblock 89 vis'made of one'of the cellular foam plastics, such as foamed polystyrene or polyurethane.` Plate 90 is mounted atop'theforward end Vof shroud 83,'the forward end of this Vgenerally cylindrical shroud 83 vhaving a fiat top. A second buoyant block 91 is mountedonthis plate `Thus, it will be seen that,

from the bottom to the top, there is an ideal. (yeteXtraordinary inthe skiing yart) gradation of density of theV component materials, all ofwhich may be freely exposed; to water. The dense compact engine andthe drive train serve as ballast, much asthe similarly positioned weighted keel would serve'y Vin a sailboat;l where'v :the-,overturning 75 and the ski-boards, which are preferably made of Wood, though they might well be of fiberglass with hollow rnidseotion, are next in density, followed by the foam on f top with its density of only 11/2 to 5 pounds per cubic y foot, the overall weight distribution being such'that the 1 structure has extreme stability 'against overturning. Re-

placing pieces 75, 76 and 77 with a one-piece cut-out board converts the fSea-Skimmer to a simple motorized" sled.

While one might apply so much buoyant material that the structure could handle a tremendous overload of unskilled skiercargo with a great margin to spare, the purpose of the comparatively small'axnountof foam shown in the figures is, rather, to keep the Sea-Skim`merv itself alloat and with the engine` running reliably under anyy high-speed maneuver and afternearly all possible kinds of spills of the skier. `The skier should be able to board it in deep water, where the usual buoyantski-jacket will make it easierfto mount. .l

The forward planing board 75 and the buoyancy material 89 have beenfcut out sufficiently in FIGS. 8 and 9 to permit raising Athe engine. and cowling 82. to a higher level with respect to the forward planing board 75. Part of the :upward-displacement of the engine u(or relative downward kmovement of the forward planing board 75 can be gained from adjuster 31.v More space can be readily gained by inVerting'left-andright brackets 78, 73 individually before again securing them to the forward planing board'75. The block of foam y91 above'the shroud 83 would also requirea clearance cut. l

In general, the raising of the engine, -cowling-82 and shroud 83, with respect to the forward planing board 75 results in a tradeoff. Speed goes up because the profile of the engine becomes less prominent in the water;` and stability decreases as Vthe ,center of mass Vof the engine moves up toward the-center of buoyancy of the foamed plastic. The turn radiusl is also increasedfby raising thel engine. y

Spring-loaded flapper valve 92,keeps the aft end of the shroud 83 blocked so as to prevent circulationy of water` therethrough and thereby .keep the Sea-Skimmer from advancing in thev water'when'it Yis unmannedl and the engine is idling. 'The valveV 92 can, therefore, be considered a dead-mani control. At idling'engine. speeds, there is sufficient slip past the propeller 84 to keep the engine from stalling evenwith the llapper valve 92 closed,

while, at the same time, insufficient thrust is developed to overcome torsion spring93 that holds valve 92 closed.

In addition, a veryslight retracting force, applied by low-rate spring 94, keeps lone .ski-board (in this case-76) slightly depressedwhen the Sea-Skimmer is unmanned, v y so that any possible-movement will be in circles.

Still another deadman control liesin the throttle spring 117, which restores' the setting to idle whenl the Sea-Skimmer is not manned.` Theflexible cable sheaths 95,96 are led togetherto grip'control 135. The control cables 197, 198which are within these sheaths, terminate respectively in controlrings 136,v 137. The skier, in the water, grasps `the igrip control 135, but does not immediately draw withl his fingers on the rings 136, 137, that disable the ,dead-manTcontrols. A single control might;

alternatively, be substituted. j 1t would first open the flap# ervalve 92l before itbegins to affect the throttle 105. Sincethe skier is somewhat' buoyant, and the aft ends of the skiaboards'76, 77 are deeply: depressed below` thek .l

rest of the Sea-Skimmer, the skier will not unduly de- Y press the craft when' he rests his feet against the ski-boards f 76, 77, as he holds grip control 1735."Y yThe forward planing `board 75 tilts back somewhat; and buoyant blocks 89, 91

will be pulled somewhat downward;but unless the skier should deliberatelyV try to drownrthe lengineby forcing the stack below the surface, or by rolling the'craftkabout Vits centerline.,"thenenginewill continue to'run.l

With his-feet vin placefagainstfthe sharply; 'tiltcdcski-oboards 76, 77, his body well down, and the buoyant blocks S9, 91 depressed somewhat, the skier draws with his fingers on rings 136, 137 that, respectively, open the iiapper valve and the throttle 1de. As the engine rpm. increases, forward motion may begin relatively slowly, the depressed skiboards 76, 77 exerting a high drag force. As the speed increases, the aft ends of the skiboards 76, 77 begin to rise. As they rise, drag lessens (the drag coeiiicient), and the engine r.p.m. increases further as the Water Velocity in shroud 83 continues to pick up. When the hump is passed, the skier is now planing. At this point, he may ease off the throttle control or keep it open, depending on whether he desires to hold his planing speed or increase it further. Should the skier fall ofi, the center of gravity of the Sea-Skimmer is so far below its center of buoyancy that it is not subject to overturning, as are all but the widest-based planing devices now in the art.

Between the independently articulated skiboards 76, 77 which rotate about pin 86 and which are held in place by snap rings 87, 87, there is a boot 88 of stiff fabric, which loops high over the shroud 85 and permits either skiboard '76, 77, or both, to be depressed at an extreme angle such as that of the skiboard 76 in FiG. 8. In FiG. 8, the boot Sii has been cut away to permit better portrayal or the propeller-shroud arrangement d3, 34, 3S, S. The purpose of the boot 3b is to protect the feet of the skier against accident during acceleration or turns. As the skiboards 76, 77 rise, the boot keeps his feet from being caught between either of the now-rising skiboards 76, 77 and the underside of the shroud 33.

It will be seen that this engine-propeller arrangement might have been reversed, that is, the engine might have been turned end for end, with its spark plug end being aft and the propeller forward. Any of several simple changes, such as reversing the direction of revolution of the engine or changing the pitch hand of the propeller, would convert the drive arrangement from the present pusher to a tractor.

Referring now to FiGS. l0, ll, l2, and 12A, there are seen an engine and a Sea-Skimmer, both of broad concept similar to that just described. The engine embodies certain alternate drive and fuel-air handling structure.

As seen in FIG. l0, the bevel gear 201 is integral with or secured to the lower crankwheel 262 in a manner like that of the prior-described bevel gear 63, and it similarly drives bevel gear 2d3 at a right angle. In this instance, the drive centerline of gear 2633 is displaced below the centerline of the engine. The engine is coupled to a shroud-shaftepropeller assembly 21d, 84, 85 very similar to the prior embodiment. The shaft and propeller S4, SS are not visible because shroud 21d has not been sectioned.

End block 269 projects aft from the end of the lower wall 204, enabling the engine to be coupled to adapter 20S by means of set screws 296 or other suitable fasteners.

In FIG. ll, the engine is seen alone from above. Like the prior-described engine, it appears unbelievably small. It may seem incredible that a dozen and more horsepower can be obtained from so slim an engine on the order of a foot long. Because of the basic efficiency of the slim configuration and nearly straight-line contour, from the spark plug cover 2S to the end of the shroud 22th, the axis of which is parallel to the axis of the combustion cylinder, very little cowling is needed to afford the maximum efficiency of hydrodynamic flow past the power plant. For similar reasons, these engines are also highly adaptable to other uses, as will be seen.

Besides the end block 2t9, there are other surfaces available for mounting purposes. These include the angularly offset swivel base 211, set at an angle to the cylinder axis that suggests wide utility for boat-type em* ployrnent, the forward end of the engine, of modified cylindrical shape, etc.

The exhaust stack embodiment is simpler than that 1@ previously described, being a simply inverted U-tube-type gas trap. For skiing applications with this engine the previously described exhaust stack 43, 44, 45 might be preferable.

The fuel system achieves the utmost in distinctive sirnplicity and protection. Virtually all that appear visible are a gas tank 221 and a dome 222. The gas tank 221 contains a hollow axial tube 226, open at both ends, in which the pulse-type carburetor 223 is fitted and secured with nut 224. 'l` he lower frange of the tank below this nut, therefore, constitutes the upper surface of the manifold 22S, which iits nicely over the reed ports 72, located in the upper wall 215, which is also the lower surface of the manifold, the arrangement being similar to that of the prior engine in general. The tube 226 extends above the fuel tank 221i, terminating within dome 222 for spray protection. The fuel-tank-to-carburetor hose 227 communicates, via the fuel tank filler cap 232, with a ilexible tube that extends to the bottom of the tank 221. The fuel tank vent is of the orthodox type, contained in the cap 232. The spring-biased choke valve is operated by lifting its bead-chain control 229 and engaging it in any desired position in the notch at the top of the tube 226. The throttle control 23@ is, as before, fed through a sheath 231i.

The Sea-Skimmer of FiGS. l0 and l2 accepts the end block 209 in transverse bulkhead 265. The forward end of the engine is supported by adjuster assembly 81, identical with that seen in FG. 8. Bulkhead 295, which closes the aft end of Cowling 216, yis secured to forward planing board 212 by angle brackets 213, 214 on each side of the fore-aft centerline of the Sea-Skimmer. Left and right angle brackets 214 have a large transverse hole 298 serving functions similar to those of the hole 274 in end wall 34 in the prior embodiment. Left and right brackets 217, 218 for ski-boards 219, 22) pivot on pin 207 which traverses hole 293. However, as distinguished from related structure in the prior embodiment, the forward planing board itself does not pivot on the pin 207 or in the hole 20S. instead, the attachment for the bulkhead 2t5 and the forward planing board 212 is effected by angle brackets 213, 214 via bolts and screw fasteners, including 235, 237.

Pan 216 is sealed against entry of salt water (optionally) by valve 386, when filled initially with fresh water. Replenishment may be made with salt water, the valve being generally left at least partly open when in fresh water.

A large buoyant block 233, which optionally may be made up of layers, as indicated by the numeral 243, is held 'in place on the forward planing board 212 by six wing nuts 234, 234 installed in the same manner as were wing nuts 94 in the prior version. The buoyant block 233 is cut out to clear gasoline tank 221 and exhaust stack 235.

As in the prior embodiment, the engine is again pic* tured in the lowest and best position insofar as stability of the craft is concerned. This time the foam plastics above the engine might appear to bar the adjuster 81 or a conventional fixed bracket from raising the engine higher. The foam plastic may, however, be easily cut or cheaply replaced, particularly in View of its layered configuration. Moreover, it will be observed that brackets other than 213, 214 might have been substituted to position the engine even higher, say, if desired, even above forward planing board 212. Such elevation of the engine, while possible, is not to be preferred, even though the stability would still be far superior to that of craft employing outboard engines.

It will be noted that the propeller shaft is well below the centerline of the engine cylinder. This gives a step construction that permits the engine to ride higher than does the propeller. It will also be seen that gears 261, 203 are smaller than those in the prior embodiment. Therefore, especially when the engine is tilted with respect to the forward planing board, liatter bottomed, smaller cowlings may be substituted for cowling 216, with some trade-oft of stability and ability to turn and corner the craft in favor of straightaway speed and planing ability.

Again, as in the prior embodiment, pin 207 is the point of pivot-coupling of the skiboards 219, 220, which extends aft to make up most of the length of the Sea- Skimmer. Again, a fabric boot 23S serves as a protector for the feet of the skier; cross 86 protects him against entry of a limb into the shroud 210; and flapper valve 92, spring-loaded, prevents advance of an unmanned Sea- Skimmer when the engine is idling. Cross 86 is not seen because shroud 210 has not been sectioned.

Ski-boards 219, 220 are shown without conventional types of foot bindings because of a fundamental difference Y between towed skis and the Sea-Skimmer. When on towed skis, the skierl himself, by body stress, must deliver all ofthe towing thrust via his feet to move the skis through the Water. Without bindings, he may be pulled forward, right oli vthe skis. In the Sea-Skimmer, on the otherV hand, the forward thrust is delivered directly by the engine to the skiing device, the task of the skier not being compounded by any need to deliver" thrust. His effort will be limited to keeping balance and delivering control impulses, via feet andV hand control, as well as the throttle, as he shifts his body to perform maneuvers. Foot impulses need not be limited to the restricted zone afforded by bindings; but bindings may be used if desired. Lacking a requirement to deliver thrust, and operating a device that Iis so light and small, compared-to his own weight, the skier may perform more complex, swift, and vspectacular maneuvers for a longer time without selftiring. Y

Referring particularly to FIGS. 12 and 12A, and momentarily back to FIGS. 9 and 9A, it may be seen that the edges of the skiboards are equippedwith thrust rails. As seen in FIG. 9, thrust rails 281 actually serve several purposes, one of which is to permit the skier to deliverr side thrust, as he would want to do, for example, when shifting his weight lto the inboard ski to execute Vav turn;

Thrust rail 281 is an elongated strip, attached byfast- .eners 282, which protrude in the drawing but are preferably ush or recessedyalong the edges of ski-boards 76 and 77, and extending well above the top surface of the ski-boards. Thrust rail 281 could be Vof wood or other solid material; but for protection against abrasions during spills it is preferably of rubber, thick and stiff enough to accept some thrust between adjacent fasteners 282.V

In FIG. 9A, thrust rails 283 lie along the edges but on top of rather than against the sides of ski-board 76. They are adhesively attached.` They are preferably of Vopencell foam of rsuch character that they will be resilient without excessive tendency to hold water. Adequately skin abrasion during spills.VV Y

In FIG. 12, ski-boards 219 and 220 'have thrust-rail means that affords still more protection against skin abrasion and at the same timeenhances controllability of the craft; The material 287,A 289 of the thrust rail, similar in character to that of thrust rails 283, carries all the way 28S, 290 around the Vedges of skiboards 219 springy, suchmaterial affords optimum protection'against 12 rapidly in chop severe enough to raise his foot momentarily from the ski-board, the foot will return to the board without spill or injury.

T-control arm 240, also pivoted on pin 207, affords a rigid, hand-operated balancing control, as contrasted with the flexible device 95, 96,135, 136, 137 used in the prior embodiment. Like the othery arrangement, it affords a means for leading throttle control 230 (seen in FIG. 10) via its sheath 231, and the apper valve control cable 241 to a common point within T-control arm 240, so as to permit use of a single spring-biased dead-man type of finger control 242,' as seen in FIG. 12. A springbiased control-arm lock, byr means of which the T-control arm may be clamped or pinned to shaft 207, is operated by withdrawing ring 243 slightly and rotating it 90, so that pin 244 no longer nds support against the crossbar of the T-control arrn.y The T-control `arm is' more effec- Y 12 affords striking contrast with-the cumbersome prior art. Looking straight down, all that can be seen of the tinyengine below are the dome 222, the top surface of the exhaust stack 235, and the throttle control cable sheath 231.Y The dotted lines show the small extent by 'which the tiny engine underneath exceeds the outline of the cutouts made in the'buoyancy block 233 for clearance of the dome and stack.

Remembering that'a typical size fornon-professional,

Vgeneral-purpose, towed water skis might be 6 feet long and 7 inches wide, with some Versions, such as Big Boy,. going to 9 feet, it is seen that the Sea Skimmer, with its overall length of6 to 6'1/2 feet andrski-board width' of 7 inches, with spacing between the ski boards being typically 5 inches or so, is comparable in size and may often be shorter than unpowered, towed skis. Withrnore than adequte power available from engines ranging from 1,0 to 20 pounds gross weight, the Sea Skimmer pays only a tiny Weight penalty for self-power, for the vcomplete freedom from towing, and the unique capability of mak-L ing fully coordinated maneuvers and-movements on splitand 220, as detailed in FIG. 12A, helping furthcrto rnnmize the possibility of bumps and bruises.

Moreover, between the cutouts 291 that arefseenat spaced intervals in FIG. 12, there are bridges 293 of theV same material connecting the left'and'right thrust rails on a ski-board and making 'the'rail means one-piece;Y In

FIG. 12A, these bridges 293Y are seenl to be elevatedV above the surface of ski-board 219. Thus, it maybe seen that the'skier can slip his foot at'will into orout of any `of the cutouts'291 in the .soft foam material 'of the thrusti-y rail means, poising either-'foot aft orJforwa'rd, as maybe;

second, one-man decision.

When it'is further realized that the depth of the Sea- Skimmer, as shown in FIG. 10, is sofshallow, its usefulness in waters that will not admit boats will be better understood. kRemembering also that the depth of the Vfoamed plastic buoyancy block 233 may be selected 24S and changed at will by loosening the wing nuts, tosuit the capabilityand weight of the skier or the roughness of thel water, and that ski-boards 219, 220 can'be simply swapped by the loosening ofa pin 207 for boards of different lengths, or widths, that the overall width of the craft may be personalized by the substitution, for example, of a longer pin 207, further realization will be Vinferred :as to :the brand-new dynamic intimacy of personalization with which the Vskier canl readily endow y his use of the versatile.FSea-Skimmerff Referring now to FIG. 13, thereisr shown a forward kplaning board 212 similar to that seen in FIG. 10.` An

air cell 249 :is mounted on-the board 2,12. The air cell desired, forexecuting a'maneuverl VHewill not lose'a ski that vsomeone will` need' to recover,vfeither. /Hefstill' retains-the advantages of the previously described thrust Yrails,'while preserving assurance that, even-,while turning Y ward planing board 212 by strip :250, 250Which'bounds its .outer periphery, and Yby strip 25,1, 251, around the ytubular clearance channel 258 provided in the cell 249 for gas tank 221 and-Y exhaust stack 235. Anfextension'ZSZ on strip 251 prevents the wall of cell 249 from contacting exhaust stack 235.` n. g Clearance channel 258 takes a right-angled turn aft near vits upper end terminating Ain air-entry 257, `angledzaft.

encinas A stretchable hose 253 is secured to the wall of air entry 257 and extends forward to air intake tube 256, which it grips with elastic cuff 254. A seal might be applied at 254; however, for this embodiment the cuff need not be water-tight, it being preferred that any water splashed into air entry 257 drain down outer wall of fuel tank 22d.

The design and employment of air cell 249 imparts to it a unique characteristic. Any force tending to submerge air cell 249 results in its being squeezed laterally inward by water pressure, which, of course, acts most strongly towards the bottom. Thus, the upper surface of air cell 249 is bulged further upward toward and perhaps beyond dotted outline 259. Hose 253fthen stretches to keep air intake 256 linked with air entry 257, automatically compensating in part for the submergence and helping to keep carburetor' and moving parts of the engine dry.

Referring now to FIG. 14, ski-boards 476, 477, otherwise identical with ski-boards 76, 77 in FIG. 9, are connected, together with middle board 483, to form a single plane surface. Straps 484, 485 are bolted in place across the three boards 476, 477, and 483. Quick-disconnect arrangements or other devices may be substituted for strap-s 484, 485. Use of this removable modification permits the Sea-Skimmer, while retaining most of its distinctive advantages, to be operated like a hinged powersurf-board, a mode that is helpful for beginners.

In FIG. l5, which represents a further variation on a portion of the structure of FIGS. 8 and 9, bracket 478 is attached to forward planing board 75 in the same manner as were left and right brackets 78, 78, described therewith. Left-hand bracket 478, however, will be seen to be extended and to have a second tran-sverse hole 490 behind the rst. Bracket 479, replacing bracket 79 of the earlier ligure, will also be longer and have a second transverse hole 491. Bracket 488, replacing bracket 88, also has a second hole, as does the right-hand bracket 478, which is hidden in this view. Lock pin 482 is interchangeable for use in the new holes on either side. When fitted through holes 498 and 491, it will align left ski-board 476 as an extension of forward planing board 75. A second lock pin 482 will similarly lock right ski-board 477 as a parallel extension of forward planing board 75. Boot 88 can then be dispensed with. Thus, the structure may be converted at any time from articulated, separately balanced skis to skis that are held rigidly in the same plane with the forward planing board 75.

Use of the middleboard 483, described with FIG. 14, together with the brackets, as modied in FIG. l5, converts the whole craft into an unarticulated motorized Surfboard, of function similar to that mentioned in column 8, lines 7-10, except that it can be converted back to the most agile mode by simply removing the parts added, that is, the middle board 483, straps 484, 485 and the lock pins 482.

Referring now to FIG. 16, the engine shown will accept most of the components described in connection with other figures, differing only in its right-angle drive, that exits via lower casting 381 but otherwise is arranged and functions identically with corresponding components in prior iigures.

Referring now specically to FIG. 17, there is seen a structural variation applicable to all engines of this invention. It embodies several distinctive characteristics. The cylinder sleeve 32.6), shown in section, with no piston in place, combines functions of a number of parts of the engines previously described. The cylinder 310 is eX- posed directly to cooling by water, the upper casting 311 and the lower casting 312 terminating just forward of the valve area.

Cylinder 31rd has bosses such as 313, 314 for holding its alignment with the walls in the ported areas of the upper and lower castings 311 and 312. A Iseal against infini: of sea water and against pressure loss in the crankcase and port regions is provided by O-ring 315. Inlet t4 ports 37, 37 perform functions identically with those so numbered in FIG. l.

Cylinder 310 is prevented from moving longitudinally with respect to upper and lower castings by its ange 316, which engirdles it. Flange 316 does not fit recess 317 longitudinally, the adjacent spaces on both sides of the ange 316 being snugly filled with shims 318, 319. A shift of any shim from one side of ilange 316 to the other will change the compression ratio of the engine because the piston travel is fixed by the crankcase projections; so movement of the shims changes the effective height of the combustion chamber 320.

Spark plug 23 and desiccant ring 30 perform the same functions as did similar parts in FIG. l. Spark plug chamber liner 321 has high dielectric strength and minimum moisture absorption. Spark plug chamber wall 322 is integral with cylinder 310 and the cylinder head.

A spring linger 323 grips the tip of spark plug 23 when high-tension, molded, sealing plug 324 is screwed into chamber 322. Sealing plug 324 consists of a high-tension wire 325, an integrally molded rubber insulator 326, a threaded metallic adapter 329, which screws into the threads at the forward end of chamber 322 and is sealed by O-ring 327. The cable 328 is normally reverse-twisted to the left a few turns before it is screwed into place to close the mouth of chamber 322.

Referring now to FIG. 18, there is shown a scheme for employing the engines of this invention generally, and particularly the engine of FIGS. 10, 11, and l2, to drive a newly envisioned class of very light-weight, low-draft, highly maneuverable, very small racing craft. For nonskiing use, except when the water is only a foot or so deep, is may be desirable to remove the shroud arrangement and replace it with the boom 260 and skag 261. The propeller shaft 262 rides in a water-lubricated bearing 263 at the end of the boom 268. The end block 269 is again the mounting point on the engine, with forward clamp 264, like 81 in the ski version, positioning the forward end of the engine. The Z-shaped engine suspension 265 pivots at its forward end in pedestal 266 and ring 267; and it terminates in steering sprocket, driven by a chain (not shown) by a prone operator forward of the transom 269.

Referring now to FIG. 19, the engine of FIGS. l0, l1, and l2 is mounted, by its obliquely set swivel-base ring seat 211, which is cast integrally into lower wall 284. Several screwed-on fingers 270, only one of which is shown, are distributed around the undersurface of ringseat 211 to hold it down while leaving it free to rotate. The engine may be installed in this manner aft of a transom, as in FIG. 18, or in the bottom 271 of any nonwatertight compartment or outboard shelf at bottom level. For use in very small, high-performance, light, shallow, agile, planing water craft, it may be steered by clampedon tiller 272 or other means. Reversing is accomplished by rotating the engine Besides their use in water-racing craft, the tiny, highperformance engines may also have capability and applicability of individually manned midget craft for military amphibious operations, because of the low silhouette, high speed, and agility that combine to make such craft dilicult targets, and because they may be adapted to run right up the beach.

It will be obvious that various combinations can be made of inventive features I have shown. Such combina tions will become immediately obvious to those skilled Ain the art without departing from the true scope of this invention. It is most obvious that major improvements over the old art can be accomplished by the adoption of only portions of the inventive features disclosed hereinabove. New equivalents of the embodiments introduced and taught here will immediately suggest themselves. It is, accordingly, intended to include in the appended claims such portions and equivalents as may fall within the true scope of my invention. I wish it to be understood that "l 5 my invention is not to be limited, to the specific forms or arrangements to which I have limitedmydescrptons, drawings and claims for the sake of brevity and expeditious prosecution, therefore, I claim;

1. A watercraft having a fore-to-aft centerline and comprisni'g:

an internal combustion engine located 4at the bottomVV level thereof along said centerline; t

a generally horizontal output power shaft extending from said engine along said centerline;

a screw propeller mounted on s aid shaft;

an elongated water planing platform structure extending forward and aft of said engine,

said engine being mounted upon said `structure and depending at least in lpart below said-structure and below thewater level of said craft,

said engine beingimmersed in water for coolingitself and ballasting said craft;

and a buoyant element surmounting said platform structure.,

2. A water craft as in claim 1, the width of the depending part of said engine being less than half `the width of said platform structure.Y

3. A water craft as in claim 1, saidcraft having external housing means guarding said propeller,

said housing means being proportioned to exclude the Y digits and limbs of a falling human operator from access to the zone of revolutionA of said propeller.

4. Awater craftasin-claim 1,

said platform being composed of a forward portion and an aft portion,

said portions being linlred bypivot means.

5. A water craft as in claim 4, Y

said aft portion consisting of separate right and left ltiboards disposed on opposite sides of said centerine,

each of said skiboards being linked to said forward portion by pivot means, j Y

whereby' said right skiboard and said left skiboard may be independently depressed.

6. A water craft having fore-to-at'centerline and comprising: Y

a structure having a hydroplaning undersurface;v an underboard propulsion system mounted to Y'said structure and longitudinally 'aligned with and along said centerline, Y

said propulsion system in turn consisting of4 an immersion-cooled internal-combustion engine depending at least in part below said vundersurface, Y a generallyhorizontal s haft'extending from said engine along said centerline and a propeller mounted on s aidshaft;4 A i buoyancy means s urmounting said structure; and air-intake means and control means communicating from above said enginedownwardly thereinito, whereby said .engine also constitutes a stabilizing keelwise ballast1 .f or said craft' and exerts a righting momenthpon said craft, veven at very large angles of roll thereof. 7. A water craft asinclaim 1, said craft having a contoured Cowling aboutsaid engine for conning water thereagainst,l andclosure means in said Cowling for regulating the j admission thereinto of water upon whichA saidjcraft v is cruising,

l said closure means being adapted to be clo sedY against V direct access thereinto of such water, whereby said cowlingmay optionally be pre-loaded with 'fresh water -when'said craft is about to cruise on s alt water. 8. A water craft as in claim i1,

' said engine having an air-mtakesystem located'theren above, e

1,052,763 stone f Feb, 11, 1913 2,058,350 Y Petrer- V oct. 20, 1936 2,089,366 Hansen il .'Aug. 10,'1937 2,333,419 Fitch'.` Nov. 2, 1943 2,404,833V Forster July 30, 1946 2,434,700Y vKeckley Jan. 20, 19,48 v2,739,581 Garrett t 11-.- Msr. 27, 1956 2,969,037 v0gt 1 12111.24, 1961 3,036,544 Magri May 29, 1962 Y jFOREIGNPATENTS 822,466 v France 1 May 31, 1937 11,141,185 FrancenL-gY MarLll, 1957 ,l said'system including an entry port at the top thereof,

1 said system having a buoyant element attached thereto near said port, y

situated at ay levelbelow the level of said port, said system including elastic conduit means below said P011, whereby, whensai d engine is subjected to plunging exc ursions during-travel over water having a disturbed surface, the said entry port is liftedby said element and enabled to remain above water. 9- A water craft asin claim 3,

said h ousingmeans having a water-circulation blocking device movably attached thereto, said device `being biased in blocking position by spring m1621115," 'Y'. 1 said water craft having operator-control means coupled to said blocking device for overcoming said spring means, whereby passage of water through said housing means is restricted whenever the operator of said eraf-t is not intentionally controlling said operator-control means to overcome said spring means and hold said blocking device out of` blocking position, and thecraft can not accidentally run away. 10. A water eraf-t as in claim 5, said water craft havinga comparatively weak spring means coupled between O ne of said ski-boards and other structure forming a part of said craft, the line of action, of said spring means having been chosen so v that a rotatingv moment is applied t-o said ski-board by said spring means, s aid rotating moment beingfof suflicient magnitude to cause saidlski-board, when no operator is aboard, to assume an attitude different from that of the other of said pair of ski-boards, 7 whereby, when theengineV is Arunning with no operator aboard, theasymmetry caused by the said different attitude will limit said craft to movement on a circular course., l i 11. A watercraft as in claimS, including flexible guard Ymeans attachedto the inboard sides of saidski-boards generally abreast of said tubular. housing means,

u vsaidiiexible guard rnea'nstbeing of sufcient length to hindrance therefrom, whereby saidguard means will not impair the functioning of said craft as a Water vehicle and will repel either kof the feetvpf-the. skierfrom being caught ybe- -tween said housing means and one of said ski-boards. 12. A water craft as in claim 5, each of vsaid siti-boards having a raised margin along the sides thereof, whereby transverse thrust can be imparted to said skiboards bythe feet of the operator thereof. 13. A water craft as in claim l2, Y the saidmargins along the, sides of each ski-board being cross-connected at intervals Valong the length thereof Y -by bridgesof flexible material, vReferences Cited in the tile vof this patent UNITED STATES PATENTS permit saidskiboardsto'be greatly depressed without 

1. A WATERCRAFT HAVING A FORE-TO-AFT CENTERLINE AND COMPRISING: AN INTERNAL COMBUSTION ENGINE LOCATED AT THE BOTTOM LEVEL THEREOF ALONG SAID CENTERLINE; A GENERALLY HORIZONTAL OUTPUT POWER SHAFT EXTENDING FROM SAID ENGINE ALONG SAID CENTERLINE; A SCREW PROPELLER MOUNTED ON SAID SHAFT; AN ELONGATED WATER PLANNING PLATFORM STRUCTURE EXTENDING FORWARD AND AFT OF SAID ENGINE, 